Ink jet head and its manufacture method

ABSTRACT

An ink jet head is formed of a nozzle material composed of a condensation product containing a hydrolysable silane compound having a fluorine-containing group and a photo-polymerizable resin composition.

TECHNICAL FIELD

This invention is in an ink jet head and its manufacture method.

BACKGROUND ART

Recently, the technical development to the improvement in a performanceof smaller droplet, higher drive frequency and more number of nozzle iscontinued in order to make the record characteristic more advanced in anink jet record system. And image recording is performed by ejectingliquid from an ejection opening as small droplet which adheres to therecording medium typified by paper.

Here, a surface treatment is becoming more important to maintainejecting performance by keeping ejecting opening surface as samecondition at any time. Moreover, it is common to wipe off the ink whichremained on the surface by e.g. rubber blade periodically to maintainthe condition of the ejecting opening surface in an ink jet head. Aliquid repellent material is demanded for easy wiping, and wipingdurability.

Moreover, when the liquid repellent layer is prepared on the surface,the liquid repellent layer needs to adhere to its lower layer, and theproblem of peeling off of liquid repellent layer may occur. Since theink used for an ink jet head is not neutral in many cases, it is alsorequired that the liquid repellent material should have durabilityagainst ink and have adhesion power to a nozzle. In addition topreventing peeling, from a viewpoint of simplification of manufacturingprocess and cost reduction, the process is desired that the nozzlematerial and liquid repellent layer is prepared all at once. That is,nozzle material itself is desired to have liquid repellency.

Various methods have so far been indicated as the liquid repellentprocessing on the surface of a nozzle in the ink jet head. However, mostof them were just the surface treatment of the formed nozzle, and thenozzle material itself did not have the liquid repellent nature.

The surface treatment method which used the fluoride containing silanecompound is indicated in Japanese Patent Publication No 10-505870 andU.S. Pat. No. 6,283,578.

However, these surface treatments were aimed at liquid repellent naturegrant, and were not those in which the liquid repellent material itselfhas patterning nature. Moreover, the liquid repellent materials that hadphotosensitivity were indicated by Japanese Patent Application Laid-OpenNo. 11-322896, Japanese Patent Application Laid-Open No. 11-335440, andJapanese Patent Application Laid-Open No. 2000-26575. These materialscould not form the solid structure like a nozzle.

When the fluorine-containing compound which is a typical liquidrepellent material is added to resin, it is well-known phenomenon thatfluorine-containing group is arranged in the surface for its low surfaceenergy, and presenting liquid repellency.

However, since fluorine-containing compounds generally have lowdissolubility to other resin, it was difficult to mix withphotosensitive resin and to use together.

Although the block copolymer having fluorine-containing group wasindicated in Japanese Patent Application Laid-Open No. 2002-105152 as acoating composition, it could not be applied to the high-precisionpatterning like nozzle forming. Japanese Patent Application Laid-OpenNo. 2002-292878 referred to the orifice plate having nozzle structure,which was made of fluorine-containing resin. Since fluorine-containingresin did not have photosensitive characteristic corresponding topatterning by photo-lithography, the nozzle had to be formed by dryetching etc. Furthermore, the inside of ink passage of a nozzle needs tobe hydrophilic in order to obtain the ejecting performance, hydrophilicprocessing needed to be performed inside of the ink passage and theadhesion side with basis material and so on.

Cationically polymerizable resin composition, which includedfluorine-containing compounds, was indicated by Japanese PatentApplication Laid-Open No. 8-290572. However, the purpose of thisinvention was the rate reduction of water absorption of material, notliquid repellency. Since the compound in this invention has hydroxylgroup for dissolubility with resin composition, the composition did notshow liquid repellency.

U.S. Pat. No. 5,644,014, EP B1 587667 and Japanese Patent PublicationNo. 3306442 referred to the liquid repellent material comprisinghydrolysable silane compounds which had fluorine-containing group.Although the above-mentioned material is indicating the photo curabilitywhich was derived from photo radical polymerization, it is not mentionedabout pattern formation using photo lithography technology nor theapplication to an ink jet head.

DISCLOSURE OF THE INVENTION

This invention is made in view of above-mentioned many points, carriedout to provide liquid repellent material of an ink jet head, which hashigh liquid repellency, high durability against the wiping (to maintainhigh liquid repellency) and the ease of wiping simultaneously, and whichrealizes high-quality image recording.

The further purpose is to offer a manufacturing method of ink jet headwhich realizes the improvement in accuracy of the ejection outletportion of a nozzle and a simple manufacturing process, by giving liquidrepellent nature to the above-mentioned nozzle material itself, andmaking a liquid repellent processing process unnecessary.

The present invention designed to attain the above-mentioned objectivesis an ink jet head, wherein the nozzle material comprises condensationproduct of hydrolysable silane compound having fluorine-containing groupand photo-polymerizable resin composition.

Another present invention designed to attain the above-mentionedobjectives is a method of manufacturing ink jet head, which is formingthe nozzle having liquid repellent nature on the surface thereof bypattern-exposure and developing a nozzle material on the substrate,wherein the nozzle material comprises condensation product of ahydrolysable silane compound having fluorine-containing group andphoto-polymerizable resin composition.

That is, the compatibility of liquid repellent material and photo resistcomposition is improved by using the above-mentioned composition. Thus,good patterning characteristic corresponding to formation of a highprecision structure like a nozzle, high liquid repellency and highwiping durability are realized without liquid repellent processing onthe surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a substrate to be used for manufacturingthe ink jet head of this invention.

FIG. 2 is a 2-2 sectional view of FIG. 1, showing an initial step ofmanufacturing the ink jet head of this invention.

FIG. 3 is a sectional view showing a step for manufacturing the ink jethead of this invention.

FIG. 4 is a sectional view showing a step for manufacturing the ink jethead of this invention.

FIG. 5 is a sectional view showing a step for manufacturing the ink jethead of this invention.

FIG. 6 is a sectional view showing a step for manufacturing the ink jethead of this invention.

FIG. 7 is a sectional view showing a step for manufacturing the ink jethead of this invention.

FIG. 8 is a sectional view showing the ink jet head of this inventionmanufactured by the steps of FIGS. 2 to 7.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail.

These inventors found out that the nozzle surface which has high liquidrepellency and high wiping durability even if liquid repellentprocessing was not performed, as a result of using the compositioncomprising condensation product containing hydrolysable silane compoundhaving fluorine-containing group and photo-polymerizable resincomposition as the nozzle material of the ink jet head.

According to the composition of the nozzle material of this invention,the cured material has the siloxane frame (Inorganic frame) formed fromthe hydrolysable silane, and a frame (Organic frame: ether bond whenusing the epoxy group) by curing the cationically polymerizable group.Thereby, a cured material becomes into the so-called organic andinorganic hybrid cured material, and durability against wiping and itsrecording liquid is improved by leaps and bounds. That is, it is thoughtthat its strength as a film improves and the wiping resistance improvescompared with liquid repellent layer formed only by the siloxane framesince liquid repellent layer of this invention has an organic frame.

Furthermore, since it is organic and inorganic hybrid material, thecompatibility of fluorine-containing compound and photo polymerizableresin composition, which was a problem conventionally, is improved. Andfluorine-containing compound which has low surface free energy is ableto mix with photo-polymerizable resin composition as nozzle material.

Subsequently, the composition material of this invention will bedescribed concretely. The hydrolysable silane compound havingfluorine-containing group, which is one of the starting materials of thecondensation product, is indispensable to have one or morenon-hydrolysable fluorine-containing group and hydrolysable substituent.

As the non-hydrolysable fluorine-containing group, straight-chain orblanched-chain fluoro-carbon group can be referred. In the case ofblanched-chain fluoro-carbon group, the terminal or the side chain ispreferred to be trifluoromethyl or pentafluoroethyl group. Owing to itssurface free energy, fluorine-containing group have tendency to arrangein the surface.

On the other hand, fluorine-containing group of the fluorosilanecontains generally at least 1, preferably at least 3 and in particularat least 5 fluorine atoms, and generally not more than 30, morepreferably not more than 25 fluorine atoms which are attached to one ormore carbon atoms. It is preferred that said carbon atoms are aliphaticincluding cycloaliphatic atoms. Further, the carbon atoms to whichfluorine atoms are attached are preferably separated by at least twoatoms from the silicon atom, which are preferably carbon and/or oxygenatoms, e.g. a C₁₋₄ alkylene or a C₁₋₄ alkylenoxy, such as an ethylene orethylenoxy linkage.

Preferred hydrolysable silanes having a fluorine-containing group arethose of general formula (1):R_(f)Si(R)_(b)X_((3−b))   (1)wherein R_(f) is a non-hydrolysable substituent having 1 to 30 fluorineatoms bonded to carbon atoms, R is a non-hydrolysable substituent, X isa hydrolysable substituent, and b is an integer from 0 to 2, preferably0 or 1 and in particular 0.

In general formula (1) the hydrolysable substituents X, which may beidentical or different from one another, are, for example, hydrogen orhalogen (F, Cl, Br or I), alkoxy (preferably C₁₋₆ alkoxy, such asmethoxy, ethoxy, n-propoxy, isopropoxy and n-butoxy, sec-butoxy,isobutoxy, and tert-butoxy), aryloxy (preferably C₆₋₁₀ aryloxy, such asphenoxy), acyloxy (preferably C₁₋₆ acyloxy, such as acetoxy orpropionyloxy), alkylcarbonyl (preferably C₂₋₇ alkycarbonyl, such asacetyl). Preferred hydrolysable substituents are halogen, alkoxy groups,and acyloxy groups. Particularly preferred hydrolysable substituents areC₁₋₄ alkoxy groups, especially methoxy and ethoxy.

The non-hydrolysable substituent R, which may be identical to ordifferent from one another, may be a non-hydrolysable substituent Rcontaining a functional group or may be a non-hydrolysable substituent Rwithout a functional group. In general formula (I) the substituent R, ifpresent, is preferably a group without a functional group.

The non-hydrolysable substituent R without a functional group is, forexample, alkyl (e.g., C₁₋₈ alkyl, preferably C₁₋₆ alkyl, such as methyl,ethyl, n-propyl, isopropyl, n-butyl, s-butyl and t-butyl, pentyl, hexyl,and octyl), cycloalkyl (e.g. C₃₋₈ cycloalkyl, such as cyclopropyl,cyclopentyl or cyclohexyl), alkenyl (e.g. C₂₋₆ alkenyl, such as vinyl,1-propenyl, 2-propenyl and butenyl), alkynyl (e.g. C₂₋₆ alkynyl, such asacetylenyl and propargyl), cycloalkenyl and cycloalkynyl (e.g. C₂₋₆alkenyl and cycloalkynyl), aryl (e.g. C₆₋₁₀ aryl, such as phenyl andnaphthyl), and corresponding arylalkyl and alkylaryl (e.g. C₇₋₁₅arylalkyl and alkylaryl, such as benzyl or tolyl). The substituent R maycontain one or more substituents, such as halogen, alkyl, aryl, andalkoxy. In formula (1) R when present is preferably methyl or ethyl.

A particular preferred substituent R_(f) is CF₃(CF₂)_(n)-Z- where n andZ are defined as defined in general formula (4) below.CF₃(CF₂)_(n)-Z-SiX₃   (4)wherein X is as defined in general compound 1 and preferably is methoxyor ethoxy, Z is a divalent organic group, and n is an integer from 0 to20, preferably 3 to 15, more preferably 5 to 10. Preferably, Z containsnot more than 10 carbon atoms and Z is more preferably a divalentalkylene or alkyleneoxy group having not more than 6 carbon atoms, suchas methylene, ethylene, propylene, butylene, methylenoxy, ethyleneoxy,propylenoxy, and butylenoxy. Most preferred is ethylene.

Specific examples are CF₃CH₂CH₂SiCl₂(CH₃), CF₃CH₂CH₂SiCl(CH₃)₂,CF₃CH₂CH₂Si(CH₃)(OCH₃)₂, CF₃CH₂CH₂SiX₃, C₂F₅CH₂CH₂SiX₃, C₄F₉CH₂CH₂SiX₃,n-C₆F₁₃CH₂CH₂SiX₃, n-C₈F₁₇CH₂CH₂SiX₃, n-C₁₀F₂₁CH₂CH₂SiX₃ (X=OCH₃, OC₂H₅or Cl); i-C₃F₇O—CH₂CH₂CH₂—SiCl₂(CH₃), n-C₆F₁₃—CH₂CH₂—SiCl(OCH₂CH₃)₂,n-C₆F₁₃—CH₂CH₂—SiCl₂ (CH₃) and n-C₆F₁₃—CH₂CH₂—SiCl(CH₃)₂. Particularlypreferred are C₂F₅—C₂H₄—SiX₃, C₄F₉—C₂H₄—SiX₃, C₆F₁₃—C₂H₄—SiX₃,C₈F₁₇-C₂H₄—SiX₃, C₁₀F₂₁—C₂H₄—SiX₃ and C₁₂F₂₅—C₂H₄—SiX₃, where X is amethoxy or ethoxy group.

Furthermore, the inventors have found that by using at least twodifferent hydrolysable silanes having a fluorine-containing group of adifferent kind unexpectedly improved results are obtained, especiallywith regard to liquid repellent properties, wiping durability, andresistance to chemicals such as recording liquid. The silanes usedpreferably differ in the number of fluorine atoms contained therein orin the length (number of carbon atoms in the chain) of thefluorine-containing substituent.

Although the reason for these improvements is not clear, the fluoroalkylgroups of different length are believed to cause a structuralarrangement of higher density, since the fluoroalkyl group should takean optimal arrangement in the uppermost surface. For example, in thecase where at least two of C₆F₁₃—C₂H₄—SiX₃, C₈F₁₇—C₂H₄—SiX₃, andC₁₀F₂₁—C₂H₄—SiX₃ (X as defined above) are used together, the highfluorine concentration in the uppermost surface is represented byfluoroalkyl groups of different length which results in the namedimprovements compared to the addition of a single fluorosilane.

Moreover, it is suitable to use together different silane compound fromabove-mentioned silane compound having fluorine-containing group, i.e.,silane compound not having fluorine-containing group, as startingmaterials of condensation reaction. In that case, adjustment of fluorinecontent, reaction control and control of the physical property becomeeasy.

Although this invention uses together above-mentioned condensationproduct and photo-polymerization composition, it is also suitable for itfrom a viewpoint of durability to introduce a polymerizable group intocondensation product.

As polymerizable substituent of hydrolysable silane compound, radicalpolymerizable group and cationically polymerizable group can be used.From a viewpoint of alkali ink resistance, cationically polymerizablegroup is desirable here.

A preferred hydrolysable silane having a cationically polymerizablegroup is a compound of general formula (2):R_(c)Si(R)_(b)X_((3−b))   (2)wherein R_(c) is a non-hydrolysable substituent having a cationicallypolymerizable group, R is a non-hydrolysable substituent, X is ahydrolysable substituent, and b is an integer from 0 to 2.

As a cationically polymerizable organic group, a cyclic ether grouprepresented epoxy group and oxetane group, a vinyl ether group etc. canbe used. In the viewpoint of availability and reaction control, an epoxygroup is preferable.

Specific examples of said substituent Rc are glycidyl or glycidyloxyC₁₋₂₀alkyl, such as γ-glycidylpropyl, β-glycidoxyethyl,δ-glycidoxybutyl, ε-glycidoxypentyl, ω-glycidoxyhexyl, and2-(3,4-epoxycyclohexyl)ethyl. The most preferred substituents R_(c) areglycidoxypropyl and epoxycyclohexylethyl.

Specific examples of corresponding silanes areg-glycidoxypropyltrimethoxysilane (GPTS),g□glycidoxypropyltriethoxysilane (GPTES),epoxycyclohexylethyltrimethoxysilane, andepoxycyclohexylethyltriethoxysilane. However, the invention is notlimited to the above-mentioned compounds.

Furthermore, in addition to the hydrolysable silane compounds havingfluorine-containing group or photo-polymerizable group, a hydrolysablesilane having at least one alkyl substituent, a silane having at leastone aryl substituent, or a silane having no non-hydrolysable substituentcan be used together for controlling the physical properties of theliquid repellent layer.

Preferred further hydrolysable silanes, which may be used in the presentinvention are those of general formula (3):R_(a)SiX_((4−a))   (3)wherein R is a non-hydrolysable substituent selected from substituted orunsubstituted alkyl and substituted or unsubstituted aryl, X is ahydrolysable substituent, and a is an integer from 0 to 3.

Tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane,methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane,ethyltrimethoxysilane, ethyl triethoxysilane, ethyltripropoxysilane,propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane,phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane,diphenyldimethoxysilane, diphenyldiethoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane, etc. are specificallymentioned. This invention is not limited to the above-mentionedcompound.

The proportion of the silanes used for preparing the condensationproduct is selected according to the application desired and is withinthe knowledge of a person skilled in the art of manufacture of inorganicpolycondensates. It has been found that the hydrolysable silanes havinga fluorine-containing group are appropriately used in amounts in therange from 0.5 to 20% by mole, preferably 1 to 10% by mole, based on thetotal amount of hydrolysable compounds used. Within these ranges a highliquid repellency as well as a very uniform surface are obtained. Thelatter is especially important for photo-curing and/or recordingapplications involving irradiation since the surface obtained oftentends to have concave and/or convex forms which affect light scattering.Thus, the above-mentioned ranges provide highly repellent, even surfaceswhich are especially suited for photo-curing and/or recordingapplications.

The proportion between the hydrolysable silane having the cationicallypolymerizable group and the further hydrolysable silane is preferably inthe range of 10:1 to 1:10.

Generally, the condensation product of the above-mentioned hydrolysablesilanes is prepared by hydrolysis and condensation of said startingcompounds in accordance with the sol-gel method, which is known to thoseskilled in the art. The sol-gel method generally comprises thehydrolysis of said hydrolysable silanes, optionally aided by acid orbasic catalysis. The hydrolysed species will condense at leastpartially. The hydrolysis and condensation reactions cause the formationof condensation products having e.g. hydroxy groups and/or oxo bridges.The hydrolysis/condensation product may be controlled by appropriatelyadjusting parameters, such as e.g. the water content for hydrolysis,temperature, period of time, pH value, solvent type, and solvent amount,in order to obtain the condensation degree and viscosity desired.

Moreover, it is also possible to use a metal alkoxide in order tocatalyse the hydrolysis and to control the degree of condensation. Forsaid metal alkoxide, the other hydrolysable compounds defined above maybe used, especially an aluminum alkoxide, a titanium alkoxide, azirconium alkoxide, and corresponding complex compounds (e.g. withacetyl acetone as the complex ligand) are appropriate.

The composite coating composition further comprises at least onecationically polymerizable organic resin, which is preferablycationically photo-polymerizable. Since an organic frame is formed bycationic polymerization (typically ether bond formation), re-hydrolysisof a siloxane frame is subdued, and the resistance to recording liquid(typically alkaline ink) is improved. Meanwhile in this invention, theinorganic frame of siloxane shows high mechanical durability againstwiping. As a result of coexistence of the organic frame and inorganicframe, it is surprisingly improved both of recording liquid resistanceand wiping durability.

The cationically polymerizable resin is preferably a cationicallypolymerisable epoxy resin known to those skilled in the art. Thecationically polymerisable resin can also be any other resin havingelectron rich nucleophilic groups such as oxetane, vinylether, vinylarylor having heteronuclear groups such as aldehydes, ketones, thioketones,diazoalkanes. Of special interest are also resins having cationicallypolymerisable ring groups such as cyclic ethers, cyclic thioethers,cyclic imines, cyclic esters (lactone), 1,3-Dioxacycloalkane (ketale),spiroorthoesters or spiroorthocarbonates.

The term “cationically polymerizable resin” herein refers to an organiccompound having at least 2 cationically polymerizable groups includingmonomers, dimers, oligomers or polymers or mixtures thereof.

Accordingly, the cationically polymerizable organic resin preferablycomprises epoxy compounds, such as monomers, dimers, oligomers, andpolymers. The epoxy compound used for the coating composition ispreferably solid state at room temperature (approx. 20° C.), morepreferably it has a melting point of 40° C. or higher.

Examples of said epoxy compound for the coating composition are epoxyresins having at least one of the structural units (1) and (2):

Further examples are epoxy resins of the bisphenol type (e.g.Bisphenol-A-diglycidylether (Araldit GY 266 (Ciba)),Bisphenol-F-diglycidylether) and epoxy resins of the novolak type, suchas phenol novolak (e.g. Poly[(phenyl-2,3-epoxypropylether)-ω-formaldehyde]) and cresol novolak aswell as cycloaliphatic epoxy resins such as e.g.4-Vinylcyclohexene-diepoxide,3,4-Epoxycyclohexane-carboxylic-acid-(3,4-epoxycyclohexylmethylesther)(UVR 6110, UVR 6128 (Union Carbide)). Additional examples areTriphenylolmethanetriglycidylether, N,N-Bis-(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)-aniline andBis-{4-[bis-(2,3-epoxypropyl)-amino]-phenyl} methane.

Concerning the epoxy resin compound, epoxy equivalent is preferably lessthan 2000, more preferably less than 1000. If epoxy equivalent exceeds2000, the degree of cross-linking decreases in the curing reaction, andsome problems may occur, decline of Tg, adhesion power to a substrateand ink-resistance etc.

The coating composition according to the present invention furthercontains a cationic initiator. The specific type of the cationicinitiator used may e.g. depend on the type of cationically polymerizablegroups present, the mode of initiation (thermal or photolytic), thetemperature, the type of radiation (in the case of photolyticinitiation) etc.

Suitable initiators include all common initiator systems, includingcationic photo-initiators, cationic thermal initiators, and combinationsthereof.

Cationic photo-initiators are preferred. Representative of cationicinitiators that can be used include onium salts, such as sulfonium,iodonium, carbonium, oxonium, silecenium, dioxolenium, aryldiazonium,selenonium, ferrocenium and immonium salts, borate salts andcorresponding salts of Lewis acids AlCl₃, TiCl₄, SnCl₄, compoundscontaining an imide structure or a triazine structure, azo compounds,perchloric acid, and peroxides. As cationic photoinitiators, aromaticsulfonium salts or aromatic iodonium salts are advantageous in view ofsensitivity and stability.

A mixing ratio by weight of condensation product and cationicallypolymerizable organic resin is preferably 0.001-1:1, more preferably itis 0.005-0.5:1.

When the mixing ratio of condensation product is lower, the liquidrepellency of the surface is not sufficient. And when higher,photo-patterning characteristic and/or adhesion power to a substrate maydecrease.

Generally, in liquid repellent layer of an ink jet head, it is desirablethat it has a flat surface with little unevenness. The liquid repellentlayer, which has unevenness, shows high liquid repellency (highadvancing contact angle or high static contact angle) against recordingliquid droplet. However when rubbing liquid repellent layer in wipingoperation etc with recording liquid, recording liquid remains in aconcave portion and the liquid repellency of liquid repellent layer maybe spoiled as a result. This phenomenon is remarkable in the embodimentthat recording liquid contains pigment, i.e., a color material particle,since the color material particle enters and adheres to the concaveportion. Therefore, as for the surface roughness Ra, which indicates theunevenness of liquid repellent layer, it is desirable to be less than5.0 nm, and it is still more desirable especially that Ra is less than1.0 nm.

In this invention, addition of the condensation product containinghydrolysable silane compound having fluorine-containing group leads tolower surface free energy, and flat surface can be obtained.

To above-mentioned nozzle forming material, it is also possible to usevarious additive agents together for the purpose of increasing thedegree of cross-linking, improvement in photo-sensitivity, prevention ofswelling, improvement of coating characteristics, improvement ofadhesion power to substrate, giving flexibility, to attain mechanicalstrength, the higher resistance against chemicals and so on. Forexample, above-mentioned photo cationic initiator can be used with areducing agent such as copper (II) trifluoromethanesulfonate, ascorbicacid etc, to attain higher degree of cross-linking. Moreover, in orderto prevent swelling and size modification of the nozzle part in ink, itis also useful to add fluorine compound in Japanese Patent ApplicationLaid-Open No. 8-290572. Furthermore, for the purpose of improvement ofadhesion power to substrate, addition of coupling agent (ex. Silanecompounds) is also effective.

Next, the manufacturing method of an ink-jet head using anabove-mentioned nozzle material will be explained.

This invention is suitable for the manufacturing method, which forms anozzle by pattern-exposure and developing. For example, it is applied tothe method which form precise nozzle structure with photo lithographytechnology using photosensitive material, indicated in Japanese PatentApplication Laid-Open Nos. 4-10940 to 4-10942, Japanese PatentApplication Laid-Open No. 6-286149, and the Japanese Patent No. 3143307etc.

For example, the following methods are mentioned. Namely, the method ofmanufacturing ink jet head comprising:

coating a nozzle material resin on a substrate,

forming nozzle plate having ink ejection opening by pattern-exposure anddeveloping of the nozzle material, and

adhere the nozzle plate on the substrate having ink ejection pressuregenerating element.

Another method of manufacturing ink jet head comprising:

forming a ink passage pattern with dissoluble resin material on asubstrate having an ink ejection pressure generating element,

forming a coating resin later by applying a polymerizable coating resinof this invention as an ink passage wall on the dissoluble resinmaterial layer,

forming an ink ejection opening by removing coating resin layer aboveink ejection pressure generating element,

dissolving the dissoluble resin material pattern,

wherein the coating resin layer contains condensation product ofhydrolysable silane compound and polymerizable resin composition.

Subsequently, it is explained the example of the ink jet head of thisinvention.

FIG. 1 is a perspective view of the substrate 1 having the ink ejectionpressure-generating element 2. FIG. 2 is a 2-2 sectional view of FIG. 1.FIG. 3 is a figure of the substrate formed ink passage pattern 3 withdissoluble resin material. It is suitably used a positive type resist,especially a photo-decomposable positive type resist with acomparatively high molecular weight, in order to prevent a collapse ofthe ink passage pattern during processing of nozzle formation.Subsequently, FIG. 4 shows that the coating resin layer 4 of thisinvention has arranged on the ink passage pattern. The coating resinlayer is polymerizable with light or thermal energy, especially cationicphoto-polymerizable. The coating resin layer can be suitably formed byspin coating, direct coating, etc. Subsequently, an ejection opening 6is formed by a pattern exposure through mask 5, as shown in FIG. 5 and,developed as shown in FIG. 6.

Subsequently, an ink supply opening 7 is suitably formed to substrate(FIG. 7), and an ink passage pattern is made to dissolve (FIG. 8).Finally, if needed, heat-treats is applied, thus the nozzle material iscured completely, and an ink jet head is completed.

The coating resin layer of this invention can be applied to a substratetwo or more times, in order to obtain desired thickness of coating. Inthis case, it is indispensable to use above-mentioned coating resincomposition as the most upper layer. Regarding lower layer, it is alsopossible to use above-mentioned coating resin composition andphoto-polymerizable resin composition not containing hydrolysablecondensation product.

In the nozzle manufacturing process of this invention, a liquidrepellent surface is obtained using hydrolysable condensation productcontaining fluorine atom, without performing a liquid repellent process.Since this liquid repellent nature is obtained at the time of anapplication and dryness, the liquid repellent nature inside of ejectionoutlet and ink passage, which formed of subsequent exposure and thedevelopment process, can be restrained and does not cause any problemconcerning its performance as ink jet head.

This invention has the feature that shows liquid repellency only for thenozzle surface through applying nozzle material on a substrate.Therefore, the mechanical methods, such as molding, laser processing anddry etching etc., can be useful also. In that case, hydrophilicprocessing is not needed, but it is used suitably.

The nozzle material in this invention has reactive group such aspolymerizable and hydrolysable group. Since those reactive groups remaineven after pattern-exposure and developing, curing reaction can bepromoted with additional light exposure or heat treatment. Thatadditional curing process has positive effect on performance of thematerial such as adhesive property, ink resistance, wiping durabilityand so on.

Embodiments SYNTHETIC EXAMPLE 1

Hydrolysable condensation product was prepared according to thefollowing procedures.

Glycidylpropyltriethoxysilane 28 g (0.1 mol), methyltriethoxysilane 18 g(0.1 mol), trideca fluoro-1, 1, 2, 2-tetrahydroctyltriethoxysilane 6.6 g(0.013 mol, equivalent for 6 mol % in total amount of the hydrolysablesilane compound), water 17.3 g, and ethanol 37 g was stirred at roomtemperature, subsequently refluxed for 24 hours, thus hydrolysablecondensation product was obtained.

Furthermore, the condensation product was diluted with 2-butanol andethanol to 20 wt % as nonvolatile content, and the hydrolysablecondensation product was obtained.

Embodiment 1

An ink jet head was produced according to the procedure shown in theabove-mentioned method in FIGS. 1 to 8.

At first, the silicone substrate 1 having the electric heat conversionelement as ink ejection pressure generating element 2 was prepared, andthe dissoluble resin layer was formed by applying polymethyl isopropenylketone (ODUR-1010, Tokyo Oka Kogyo Kabushiki Kaisha) by spin coating onthe silicone substrate. Subsequently, after prebaking at 120° C. for 6minutes, pattern exposure of ink passage was performed by mask alignerUX3000 (USHIO Electrical Machinery).

Exposure time was for 3 minutes, and development was carried out withmethyl isobutyl ketone/xylene=2/1, and rinsed with xylene.

Said polymethyl isopropeny ketone is the so-called positive type resist,which decomposes and becomes soluble to the organic solvent by UVirradiation. The pattern formed with the dissoluble resin material wasthe portion which was not exposed in the case of pattern exposure, andbecame the ink supply passage 3 (FIG. 3). In addition, the thickness ofthe dissoluble resin material layer after development was 20micrometers. Subsequently, A cationic photo-polymerizable coating resinshown in Table 1 was dissolved in methyl isobutyl ketone/xylene mixturesolvent by 55 wt % as solid content, and applied on the substrate 1 withink passage pattern 3 of dissoluble resin material layer by spincoating, and prebaking was performed at 90° C. for four minutes. Thethickness of the coating resin layer 4 on ink passage pattern was 55micrometers after repeating this application and prebaking 3 times (FIG.4).

TABLE 1 Composition 1 hydrolysable hydrolysable condensation 25 partscondensation product of synthetic example product 1 (20 wt %) Epoxyresin EHPE-3150 (Daicel Chemical) 100 parts Additive 1,4-HFAB (CentralGlass) 20 parts photo cationic SP172, Asahi Denka Industry 5 partsinitiator Reducing agent copper (II) trifluoromethanesulfonate 0.5 partsSilane coupling A187 (Nippon Unicar) 5 parts agent 1,4-HFAB:(1,4-bis(2-hydroxyhexafluoroisopropyl)benzene)

Subsequently, pattern exposure of the ink ejection opening was appliedusing mask aligner “MPA600 super” made by CANON (FIG. 5).

Next, the ejection opening pattern 6 was formed through heating at 90degrees C. for 4 minutes, developing by methyl isobutyl ketone(MIBK)/xylene=2/3 and performing a rinse with isopropyl alcohol. Thecoating resin layer was cured by the photo cationic polymerizationexcept the ejection opening pattern, and the ejection opening patternwhich had sharp edge was obtained (FIG. 6). Subsequently, mask forforming ink supply opening in the back side of the substrate wasarranged suitably, and ink supply opening 7 was formed by anisotropicetching of silicone substrate (FIG. 7). The surface of the substratehaving the nozzle was protected by a rubber film during anisotropicetching of silicone. The rubber protective film was removed aftercompleting anisotropic etching, and further the dissoluble resinmaterial layer forming ink passage pattern was decomposed by irradiatingUV using said UX3000 on the whole surface again. Subsequently, the inkpassage pattern 3 dissolved by immersing into methyl lactate for 1 hourwhile giving an ultrasonic wave to said substrate. Subsequently, inorder to cure the coating resin layer 4 completely, heat treatment wasperformed at 200 degrees C. for 1 hour (FIG. 8). Finally, an ink jethead was completed by adhering the ink supply member on the ink supplyopening.

Embodiment 2

An ink jet head was produced like embodiment 1 except for applyingcomposition 2 shown in Table 2 instead of the composition 1 asunderlayer, which application and prebaking were repeated twice, and asthe most upper layer above-mentioned composition 1 was applied.

TABLE 2 Composition 2 Epoxy resin EHPE-3150, Daicel Chemical 100 partsAdditive 1,4-HFAB, Central Glass 20 parts photo cationic SP172, AsahiDenka Industry 5 parts initiator Reducing agent copper (II)trifluoromethanesulfonate 0.5 parts Silane coupling A187, Nippon Unicar5 parts agent 1,4-HFAB: (1,4-bis(2-hydroxyhexafluoroisopropyl)benzene)

Embodiment 3

An ink jet head was made like embodiments, except for using thecomposition 3 shown in Table 3 instead of the composition 1.

TABLE 3 Composition 3 hydrolysable hydrolysable condensation 5 partscondensation product of synthetic example product 1 (20 wt %) Epoxyresin EHPE-3150, Daicel Chemical 100 parts Additive 1,4-HFAB, CentralGlass 20 parts photo cationic SP172, Asahi Denka Industry 5 partsinitiator Silane coupling A187, Nippon Unicar 5 parts agent 1,4-HFAB:(1,4-bis(2-hydroxyhexafluoroisopropyl)benzene)

Embodiment 4

Using the composition 3 shown in Table 3, an ink jet head was producedcompletely like embodiment 1, except for an application and an prebakingwere performed only once, and thickness of the coating resin layer was20 micrometers of on an ink passage pattern.

<Evaluation of Printing Quality>

The obtained ink jet recording head of Embodiments 1 to was filled upwith ink BCI-3Bk (Canon) and printing was carried out. And the highlyquality image was obtained.

<Evaluation of Wiping Durability>

When printing again after performing wiping operation 30000 times withthe HNBR rubber blade while spraying ink for the nozzle surface of thisink jet head, the same high-quality image as before wiping could beobtained. Thus wiping durability was proved to be excellent.

<Preservation Property>

Furthermore, after this ink jet head was filled up with theabove-mentioned ink, preserved at 60 degrees C. for two months. Theprinting quality was the same as before preservation.

<Evaluation of Liquid Repellency>

Moreover, both values of advancing and receding contact angle againstink BCI-3Bk for an ink jet head was high. And liquid repellency wasexcellent (Table 4).

<Surface Roughness>

The surface roughness of this ink jet head was measured in contact modeusing scanning probe model microscope JSPM-4210. The surface roughnessis Index Ra was 0.2 to 0.3 nm (it scans on 10-micrometer square), andthe surface of this nozzle material was confirmed to be very flat andsmooth (Table 4).

<Elementary Analysis of Surface>

Furthermore, surface analysis by ESCA (Electron Spectroscopy forChemical Analysis) was performed with the measurement angle of 6 degreesby Quantum 2000 (Ulvac-phi).

When the ratio of four elements of C, O, Si, and F is measured, it wasobserved that F atom was arranged on the surface at higher content thanthe calculated value 6 atom % (Table 4).

TABLE 4 (Evaluation result) Embodi- Embodi- Embodi- Embodi- ment mentment ment 1 2 3 4 Printing quality good good good good (First stage)Printing quality good good good good (after wiping) Printing qualitygood good good good (After a preservation) Advancing contact 83 83 87 87angle Receding contact 57 55 63 62 angle Surface roughness 0.3 0.4 0.30.2 Ra/nm Surface fluoride 32 32 38 38 atom ratio/atom %

1. An ink jet head, comprising: an orifice plate portion including anink ejection opening penetrating the orifice plate portion from an inletside to an outlet side; and a substrate including an energy generatingelement for generating energy used for discharging ink from the inkejection opening, the energy generating element facing the inlet side ofthe ink ejection opening, wherein said orifice plate portion is formedentirely of a cured product obtained from a material comprising acomposition comprising a polymerizable resin having an epoxy group or anoxetanyl group and a condensation product of a hydrolysable silanecompound having a fluorine-containing group and a hydrolysable silanecompound having an epoxy group or an oxetanyl group, and wherein a firstsurface of said orifice plate portion containing the inlet side of theink ejection opening has a lower liquid repellency than a second surfaceof said orifice plate portion containing the outlet side of the inkejection opening.
 2. An ink jet head according to claim 1, wherein thepolymerizable resin is an epoxy compound that is solid at roomtemperature.
 3. An ink jet head according to claim 1, wherein thecondensation product is a condensation product of a hydrolysable silanecompound having a fluorine-containing group, a hydrolysable silanecompound having an epoxy group or an oxetanyl group and a hydrolysablesilane compound selected from a silane having at least one alkylsubstituent, a silane having at least one aryl substituent or a silanehaving four hydrolysable substituents.
 4. An ink jet head according toclaim 1, wherein the hydrolysable silane compound having afluorine-containing group has three hydrolysable substituents.
 5. An inkjet head according to claim 4, wherein the hydrolysable silane compoundselected from a silane having at least one alkyl substituent, a silanehaving at least one aryl substituent or a silane having nonon-hydrolysable substituent is represented by general formula (3):R_(a)SiX(_(4−a))   (3) wherein R is a non-hydrolysable substituentselected from substituted or unsubstituted alkyl groups and substitutedor unsubstituted aryl groups, X is a hydrolysable substituent, and a isan integer from 0 to
 3. 6. An ink jet head according to claim 1, whereinthe hydrolysable silane compound having a fluorine-containing group isrepresented by general formula (1):R_(f)Si(R)_(b)X(_(3−b))   (1) wherein R_(f) is a non-hydrolysablesubstituent having 1 to 30 fluorine atoms bonded to a carbon atom, R isa non-hydrolysable substituent, X is a hydrolysable substituent, and bis an integer from 0 to
 2. 7. An ink jet head according to claim 6,wherein the non-hydrolysable substituent R_(f) has at least 5 fluorineatoms bonded to a carbon atom.
 8. An ink jet head according to claim 6,wherein the condensation product is a condensation product of at leasttwo hydrolysable silane compounds having a fluorine-containing group,the silane compounds having a different number of fluorine atomscontained therein.
 9. An ink jet head according to claim 1, wherein thehydrolysable silane compound having an epoxy group or an oxetanyl groupis represented by general formula (2):R_(c)Si(R)_(b)X(_(3-b))   (2) wherein R_(c) is a non-hydrolysablesubstituent having a cationic polymerizable group, R is anon-hydrolysable substituent, X is a hydrolysable substituent, and b isan integer from 0 to
 2. 10. An ink jet head according to claim 1,wherein the molar ratio of the hydrolysable silane compound having afluorine-containing group is 0.5 to 20 mol %, based on the total amountof hydrolysable compounds.
 11. An ink jet head according to any ofclaims 1, 2, 3, 4, and 6-10, wherein the mixing ratio (A):(B) by weightof (A) the condensation product of a hydrolysable silane compound havinga fluorine-containing group and (B) the composition is from 0.001:1 to1:1.
 12. ink jet head according to claim 1, wherein said substrate andsaid orifice plate portion are bonded to be in contact with each other.